## Containers and Processes { #containers-and-processes }

A **container image** normally includes in its metadata the default program or command that should be run when the **container** is started and the parameters to be passed to that program. Very similar to what would be if it was in the command line.

When a **container** is started, it will run that command/program (although you can override it and make it run a different command/program).

        subgraph venv2[.venv]
            harry-3[harry v3]
        end
    end
    stone-project ~~~ azkaban-project
```

## What Does Activating a Virtual Environment Mean { #what-does-activating-a-virtual-environment-mean }

When you activate a virtual environment, for example with:

//// tab | Linux, macOS

<div class="termy">

```console
$ source .venv/bin/activate
```

### FastAPI Data Filtering { #fastapi-data-filtering }

Now, for FastAPI, it will see the return type and make sure that what you return includes **only** the fields that are declared in the type.

          <type>String</type>
          <description>The groupId when this directory represents "groupId/artifactId" or "groupId/artifactId/version".</description>
        </field>
        <field>
          <name>artifactId</name>
          <version>1.0.0+</version>
          <type>String</type>
          <description>The artifactId when this directory represents "groupId/artifactId" or "groupId/artifactId/version".</description>

      }

      val now = backend.nanoTime()
      var minDelayNanos = Long.MAX_VALUE
      var readyTask: Task? = null
      var multipleReadyTasks = false

      // Decide what to run. This loop's goal wants to:
      //  * Find out what this thread should do (either run a task or sleep)
      //  * Find out if there's enough work to start another thread.
      eachQueue@ for (queue in readyQueues) {

## Be Nice

First of all, be nice. 😊

You probably are super nice if you were added to the team, but it's worth mentioning it. 🤓

### When Things are Difficult

When things are great, everything is easier, so that doesn't need much instructions. But when things are difficult, here are some guidelines.

has-password) [ -n "${MVNW_USERNAME-}" ] || MVNW_USERNAME='' MVNW_PASSWORD='' ;;
esac

if [ -z "${MVNW_USERNAME-}" ] && command -v wget >/dev/null; then
  verbose "Found wget ... using wget"
  wget ${__MVNW_QUIET_WGET:+"$__MVNW_QUIET_WGET"} "$distributionUrl" -O "$TMP_DOWNLOAD_DIR/$distributionUrlName" || die "wget: Failed to fetch $distributionUrl"
elif [ -z "${MVNW_USERNAME-}" ] && command -v curl >/dev/null; then
  verbose "Found curl ... using curl"

## Program and Process { #program-and-process }

We will talk a lot about the running "**process**", so it's useful to have clarity about what it means, and what's the difference with the word "**program**".

### What is a Program { #what-is-a-program }

The word **program** is commonly used to describe many things:

* The **code** that you write, the **Python files**.

```Python
q: str | None = Query(default=None, max_length=50)
```

This will validate the data, show a clear error when the data is not valid, and document the parameter in the OpenAPI schema *path operation*.

### `Query` as the default value or in `Annotated` { #query-as-the-default-value-or-in-annotated }

Keep in mind that when using `Query` inside of `Annotated` you cannot use the `default` parameter for `Query`.

    * Follow me to see when I create a new Open Source project.
* <a href="https://x.com/tiangolo" class="external-link" target="_blank">Follow me on **X (Twitter)**</a> or <a href="https://fosstodon.org/@tiangolo" class="external-link" target="_blank">Mastodon</a>.
    * Tell me how you use FastAPI (I love to hear that).
    * Hear when I make announcements or release new tools.